Theory of chiral modulations in confining structures: epitaxial films of cubic helimagnets

限制结构中的手性调制理论：立方螺旋磁体的外延膜

基本信息

批准号：
240641318
负责人：
Professor Dr. Alexei N. Bogdanov
金额：
--
依托单位：
Institut für Theoretische Festkörperphysik
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2017-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/240641318?language=en
关键词：
Theory chiral modulations confining structures

项目摘要

Recently synthesized epitaxial thin films of cubic helimagnets with non-centrosymmetric B20 structure (MnSi, FeGe, and others) represent a novel class of nanomagnetic systems exhibiting many physical phenomena unknown in bulk helimagnets. In particular, nanolayers of cubic helimagnets enable the observation of specific particle-like structures (skyrmions) predicted theoretically more than twenty years ago and the field-induced unwinding of helicoids via quantized steps. Our recent studies show that in nanolayers of cubic helimagnets the interplay between intrinsic chirality, structural confinement, and surface/interface induced interactions leads to the formation of specific confined chiral modulations which fundamentally differ from those commonly observed in bulk helimagnets. The aim of the project is to give a comprehensive theoretical description of confined chiral modulations and, thus, to establish physical relations between specific effects arising in cubic helimagnet nanolayers and peculiarities of their structures. Within the standard micromagnetic theory of helimagnetism rigorous solutions for helical and skyrmionic modulations in thin layers of cubic helimagnets will be derived in broad ranges of the thermodynamic parameters. Our theoretical findings will be used to construct magnetic phase diagrams for nanolayers of cubic helimagnets with different types of induced magnetic anisotropy. These results will be applied for detailed analyses of recent experiments in epitaxial films of MnSi and FeGe and to elucidate complex magnetization processes observed in these systems. They also should provide the theoretical basis for the emerging nanophysics of confined chiral modulations and supply practical recommendations for future investigations.

最近，具有非中心对称B20结构（MNSI，FEGE等）的Cutic Helimagnets的外延薄膜（MNSI，FEGE等）代表了一类新型的纳米磁系统，在散装helimagnets中表现出许多未知的纳米磁系统。特别是，立方helimagnets的纳米层能够观察特定的粒子样结构（Skyrmions）在理论上预测了二十多年前，并且通过量化的步骤通过田间引起的螺旋螺旋体的解体。我们最近的研究表明，在立方helimagnets的纳米层中，内在的手性，结构限制和表面/界面引起的相互作用之间的相互作用导致形成特定的受限性手性调节，这与散装helimagnets中通常观察到的那些基本上有所不同。该项目的目的是对受限制的手性调制的全面理论描述，从而在Cubic Helimagnet Nanolayers中建立特定效应与其结构的特殊性之间建立身体关系。在标准的helimagnetism helimagnetism的微磁理论中，在螺旋形和纯净的Cubic Helimagnets薄层中，将以热力学参数的广泛范围得出。我们的理论发现将用于构建具有不同类型的诱导磁各向异性的立方helimagnets的纳米层的磁相图。这些结果将用于详细分析MNSI和FEGE外延膜的最新实验，并阐明在这些系统中观察到的复杂磁化过程。他们还应为受到严格的手性调制的新兴纳米物理学提供理论基础，并为将来的调查提供实用的建议。